Electrochemical method and apparatus for forming a vacuum in a sealed enclosure

ABSTRACT

An apparatus for forming a vacuum in a sealed enclosure through an electrochemical reaction includes an electrochemical cell comprising a cathode and an anode supported on a solid electrolyte. The solid electrolyte is a Li-ion non-volatile electrolyte containing a dissolved metal salt. The cathode is constructed of a material with which lithium is known to form alloys. The anode is constructed of a lithium-ion containing material. The cell is operable to expose lithium metal on the cathode.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/887,489, filed Oct. 7, 2013, the disclosure of which is herebyincorporated by reference in its entirety. This application also claimsthe benefit of U.S. Provisional Application Ser. No. 61/973,428, filedApr. 1, 2014, the disclosure of which is hereby incorporated byreference in its entirety.

TECHNICAL FIELD

The invention relates generally to forming a vacuum in a sealedenclosure. More particularly, the invention relates to a system, method,and apparatus for forming a vacuum in a sealed enclosure through anelectrochemical reaction.

BACKGROUND OF THE INVENTION

There are many scenarios in which it may be desirable to form a vacuumin a sealed enclosure. One such scenario involves the manufacture ofvacuum insulated panels (“VIPs”). VIPs are a form of thermal insulationthat provides an excellent level of thermal resistance (R-value) in apackage that is very thin in comparison with the thickness of comparableconventional insulating materials (e.g., rolls and batts, loose-fill,rigid foam, and foam-in-place insulation). VIPs having a thickness ofless than an inch can provide an R-value that would require severalinches or even feet of traditional thermal insulation materials.

Because of these features, VIPs are attractive insulation alternativesin a wide range of applications where space and/or high thermalresistance is desired. Potential applications range from residential andcommercial building construction, commercial and industrialfurnace/refrigeration applications, medical storage and transport,residential appliances, etc. The high R-value, low thickness features ofVIPs beneficially reduces the space considerations required forengineering these products and, for example, can lead to refrigeratorswith more storage, ovens with larger capacities, and medical suppliesthat can last longer in extreme field conditions.

VIPs include a gas-tight or nearly gas-tight enclosure, surrounding arigid or semi-rigid core material, in which the air has been evacuatedto form a vacuum. The VIP is typically constructed of overlying gasimpermeable membrane panels that are sealed around their peripheries todefine the enclosure. The core material is constructed of a highlyporous material. The core material can have various materialconstructions and configurations. For example, the core material can bea panel of material (e.g., a sheet of glass fiber) positioned betweenthe membranes or a bulk material (e.g., a loose fiber or foam)distributed evenly between the membranes. When the air is evacuated fromthe enclosure, the external pressure applied to the membranes compressthe core which, in response, maintains some degree of spacing betweenthe membranes. The porous core material provides the space between themembranes in which the vacuum is formed.

VIPs are costly in comparison to conventional forms of thermalinsulation materials. One factor that lends to this cost differential isthe high cost of manufacture of the VIPs. These manufacturing costs aredriven not only by high material costs, but also by costly manufacturingequipment. The vacuum pumps traditionally used to evacuate air from theVIPs are costly pieces of equipment. Additionally, because the vacuumpumps require access to the VIP enclosure to draw the vacuum,maintaining and completing the seal between the membranes after the pumpis removed requires additional equipment and cost.

SUMMARY OF THE INVENTION

The present invention relates to a system, method, and apparatus forforming a vacuum in a sealed enclosure through an electrochemicalreaction.

According to one aspect, an apparatus for forming a vacuum in a sealedenclosure through an electrochemical reaction includes anelectrochemical cell comprising a cathode and an anode supported on asolid electrolyte. The solid electrolyte is a non-volatile, Li-ionconducting electrolyte containing a dissolved Li salt, the cathode isconstructed of a material with which lithium is known to form alloys,such as silicon or tin, and the anode is constructed of a lithium-ioncontaining material. The cell is operable to expose the lithium alloycathode to the environment within the enclosure.

According to another aspect, the cathode can be constructed of at leastone of nickel, copper, silicon, and tin. Other materials could also beused.

According to another aspect, the solid electrolyte can include a solidpolymer electrolyte (“SPE”).

According to another aspect, the SPE can include a lithiumhexafluorophosphate (LiPF₆) solution in polyethylene oxide (“PEO”).

According to another aspect, the anode can be constructed of a lithiumalloy that preferably should not be exposed to the gas in the enclosure.

According to another aspect, the solid electrolyte can have a thin,flat, and elongated planar configuration, wherein the cathode and anodeare deposited on in an interdigitated configuration.

According to another aspect, the electrochemical cell can have aconstruction capable of conforming to the shape of a portion of theenclosure.

According to another aspect, the apparatus includes a source of power,such as a battery, for powering the cell.

According to another aspect, the cathode can be constructed of amaterial that does not form alloys with lithium, such as copper ornickel, wherein the electrochemical cell when actuated deposits lithiummetal from the solid electrolyte onto the cathode while the anodereleases lithium ions into the solid electrolyte. The gases within theenclosure permeate solid electrolyte and react with the lithium metal onthe cathode.

According to another aspect, the cathode can be constructed of amaterial that forms alloys with lithium, such as silicon and tin,wherein the cell is operable to cause lithium to intercalate in thecathode, causing the cathode to rupture and expose the lithium alloy tothe gases in the enclosure.

According to another aspect, the solid electrolyte can be a solidpolymer electrolyte (“SPE”) including a Li-ion non-volatile electrolytecontaining a dissolved metal salt.

According to another aspect, the anode can be constructed of a lithiatedtransition metal oxide, such as lithium cobalt oxide (LiCoO₂).

According to another aspect, the cathode can be constructed of aconducting material such as copper or nickel serving as a currentcollector coated with a layer of silicon or tin.

According to another aspect, the apparatus can include actuation meansincluding sensors and electronics or circuitry that is adapted toactivate the apparatus remotely from outside the enclosure.

According to another aspect, the actuation means can be adapted tomonitor pressure in the enclosure and activate/deactivate the apparatusin response to pressure in the enclosure.

According to another aspect, the actuation means can be adapted fornon-electronic manual or mechanical activation, which can include atleast one of a rupturable member that, when destroyed, actuates theelectronics or circuitry; a removable member that, when removedmanually, actuates the electronics or circuitry; and a mechanism that isactuated magnetically to actuate the electronics or circuitry.

According to another aspect, the actuation means can include at leastone of RF transducers, tags, interrogators, and receivers adapted toprovide information regarding the apparatus and actuate the apparatus inresponse to an RF signal applied externally to the enclosure via acontroller.

According to another aspect, the actuation means can include sealedelectrical feedthroughs in the walls of the enclosure that provide forwired connections to the apparatus from outside the enclosure.

According to another aspect, the actuation means can include a wirelessinductive charging power supply.

According to another aspect, a method for forming a vacuum in anenclosed structure can include providing an enclosure; providing anelectrochemical cell with a cathode exposed to the gases in theenclosure; and activating the electrochemical cell to causeelectrodeposition of a reactive metal on the cathode. Reactive metal onthe cathode reacts with the gases in the enclosure to reduce thepressure in the enclosure.

According to another aspect, the step of providing an electrochemicalcell can include providing a solid electrolyte; providing a cathode onthe solid electrolyte, the cathode comprising a material with whichlithium does not form alloys, such as nickel or copper; and providing ananode on the solid electrolyte. The anode can include a lithium-ioncontaining material, such as a lithium alloy or a lithiated transitionmetal oxide.

According to another aspect, a method for forming a vacuum in anenclosed structure can include operating an electrochemical cell toelectrodeposit lithium onto an electrode (cathode); and reacting thelithium with non-noble gases in a sealed enclosure to consume thosegases and thereby lower the pressure in the enclosure.

According to another aspect, a method for forming a vacuum in anenclosed structure can include providing an enclosure; providing anelectrochemical cell with a cathode exposed to the gases in theenclosure; and activating the electrochemical cell to causeintercalation of a reactive metal into the cathode of theelectrochemical cell. The intercalation of the reactive metal in thecathode causing the cathode to crack or fissure, which exposes the metalto the gases in the enclosure. The metal alloy reacts with the gases,thereby reducing the pressure in the enclosure.

According to another aspect, a method for forming a vacuum in anenclosed structure can include operating an electrochemical cell to formlithium alloys on a cathode through intercalation with the materials ofthe cathode; and reacting the lithium alloy with non-noble gases in asealed enclosure to consume those gases and thereby lower the pressurein the enclosure. The method can also include rupturing the lithiumalloy cathode through intercalation to further expose gases in thesealed enclosure to the lithium alloy.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the invention will become apparentto those skilled in the art to which the invention relates upon readingthe following description with reference to the accompanying drawings,in which:

FIG. 1 illustrates a system for forming a vacuum in a sealed enclosurethrough an electrochemical reaction.

FIG. 2 illustrates a portion of the system of FIG. 1.

FIG. 3 illustrates portion of the system indicated generally at III-IIIin FIG. 2, according a first embodiment of the invention.

FIGS. 4-6 illustrate processes performed by the system in accordancewith the first embodiment.

FIG. 7 illustrates portion of the system indicated generally at VII-VIIin FIG. 2, according to a second embodiment of the invention.

FIGS. 8-9 illustrate processes performed by the system accordance withthe second embodiment.

FIG. 10 illustrates a portion of the system of FIG. 1, according toanother embodiment.

DESCRIPTION

The invention relates generally to forming a vacuum in a sealedenclosure. More particularly, the invention relates to a system, method,and apparatus for forming a vacuum in a sealed enclosure through anelectrochemical reaction.

According to the invention, a system 10 includes an apparatus 20 forforming a vacuum in a sealed enclosure 12. Referring to FIG. 2, theapparatus 20 includes an electrochemical cell 22 and a power source 24,such as a lithium-ion battery, for supplying power to the cell. Theenclosure 12 can be any enclosure in which a vacuum is to be created.Thus, the enclosure 12 is represented schematically in FIG. 1 with theunderstanding that the enclosure can have any desired shape and/or size.Additionally, the enclosure 12 can be constructed of any desiredmaterial as long as that material is compatible with the materials usedto form the apparatus 20 and the processes in which the apparatus isused, as described herein.

Referring to FIG. 2, the electrochemical cell 20 includes a cathode 40and an anode 50 supported on a solid electrolyte 30, such as a solidpolymer electrolyte (“SPE”) or a solid Li⁺ conductive material such asLISICON and LIPON, the most common inorganic Li⁺ conductors,. In FIG. 2.the SPE 30 is a lithium-ion (“Li-ion”) conductor polymer. Theelectrochemical cell 20 thus has a solid-state construction. Theelectrochemical cell 20 either: a) does not include a casing, or b)includes a casing that permits contact between the cell and theenvironment of the enclosed structure 12.

The SPE 30 is formed of a non-volatile polymer electrolyte material. Forexample, the SPE 30 could be a Li-ion non-volatile polymer electrolytematerial. In one such example, the SPE 30 can be an electrolytecontaining a dissolved metal salt, such as a lithium hexafluorophosphate(LiPF₆) solution in polyethylene oxide (“PEO”). The electrochemical cell20 can thus have a solid state construction.

Alternatively, the SPE 30 can include nanoparticles of alumina orsilica, which are known to increase lithium ion conductivity. The SPE 30can also include non-volatile ionic liquids, such as those based onimidazolium ions, which are also known to increase lithium ionconductivity. One particular example of such a liquid is1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf).

The solid electrolyte 30 used in the electrochemical cell 20 is notlimited to a solid polymer electrolyte construction. The solidelectrolyte could, for example, be a mixture of inorganic polymers orcould be two layers—an inorganic and a polymer. These configurations canprotect the anode material that is not stable by itself toward reactionwith gases, such as alloys or low voltage lithium compounds (e.g.,lithium titanium oxide “LTO”), which require a much lower voltage torun/charge. The solid electrolyte 30 could also be a mixture of polymersand ionic liquids where both display negligible vapor pressure.

As a further alternative, the electrochemical cell 20 could include aninert separator, such as commercial polyethylene (“PE”) or polypropylene(“PP”) separators, that mechanically supports the electrolyte in itspores. This can be beneficial, for example, in the case where thepolymer or mixture is too weak to support the electrodes or to supportrolling, folding, or otherwise shaping the cell 20 in the desiredmanner.

The cathode 40 can be made of materials such as nickel (Ni) or copper(Cu), with which lithium does not form alloys at room temperature; ofsilicon (Si) or tin (Sn), with which lithium is known to form alloysunder room temperature conditions; or of carbons, into which Li-ion isknown to intercalate. The cathode can incorporate the use of a currentcollector made out of Cu or Ni onto which silicon and tin can bedeposited either as films or in the form of small particles supported ona highly conducting material such as carbon using a non volatilepolymeric binder.

The anode 50 includes a material capable of donating reactive metal ionsto the SPE. Examples of such metals are group I metals, such as lithium(Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).Lithium, however, is the metal best suited for the applicationsdisclosed herein and is therefore preferred. Therefore, the anode 50could include metallic lithium and any material that contains Li and canlose Li-ions without gas emission, which might be protected by a gasimpermeable electrolyte layer preferably inorganic and thus chemicallyless reactive. For example, the anode 50 can be made of Li+containingmaterial, such as a Li alloy or a lithiated transition metal oxide, suchas lithium cobalt oxide (LiCoO₂).

Lithium, while preferred, is not the only possible reactive metal. Forinstance, NASICON (a sodium ionic super conductor material) is a goodNa⁺ ion conductor that could be used for the solid electrolyte 30. Touse this material as an electrolyte, the anode and cathode materialswould have to be formed from matched materials that use Na as the activemetal.

This description of the invention illustrates and describes embodimentsthat utilize lithium as the reactive metal in the electrochemical cell.While lithium is the preferred metal, this description is not meant tobe limiting, as those skilled in the art will appreciate that otherreactive metals (e.g., those listed above) could potentially be used inthe construction of the apparatus 20 and thereby to carry out thereactions and processes described herein.

In the embodiment illustrated in FIG. 2, the SPE 30 has a thin, flat,and elongated planar configuration. The cathode 40 and anode 50 aredeposited on the SPE 30. The cathode 40 includes a bus portion 42 thatextends along a longitudinal edge of the SPE 30. The cathode 40 alsoincludes a plurality of tabs or fingers 44 spaced along its length andextending transversely from the bus portion 42 in a generally downwarddirection as viewed in FIG. 2. The anode 50 includes a bus portion 52that extends along a longitudinal edge of the SPE 30 opposite the busportion 42. The anode 50 also includes a plurality of tabs or fingers 54spaced along its length and extending transversely from the bus portion52 in a generally upward direction as viewed in FIG. 2. The fingers 44,54 of the cathode 40 and anode 50 are arranged in an alternating andinterlocking manner referred to herein and in the art as“interdigitated.” This repeating, interdigitated configuration allowsthe apparatus to have any desired length.

The SPE 30, cathode 40, and anode 50 can be extremely thin, e.g., in therange of several hundredths or thousandths of an inch thick. Theelectrochemical cell 20 can thus have a correspondingly thinconstruction. The SPE 30, cathode 40, anode 50, and, thus, the apparatus20, can, of course, be thicker. Advantageously, this thin, elongated,planar configuration, in combination with its material construction,allows the electrochemical cell 20 to be bent, rolled, folded, andotherwise manipulated to assume a desired shape, configuration, or form.For example, the electrochemical cell 20, having this construction, canbe made to conform to the shape of a portion of the enclosure 12 (seeFIG. 1) in which it is implemented.

The thin film electrochemical cell construction illustrated in FIG. 2 isbut one illustrative example construction of the cell. Theelectrochemical cell 20 could have configurations/constructionsalternative to the thin film configuration described above. For example,the electrochemical cell 20 can have other film configurations or couldbe constructed in the form of a pellet, cylinder, block, or any otherdesired configuration having electrodes and electrolyte arranged in amanner that is consistent with the operation described herein.

According to the invention, the electrochemical cell 20 is adapted toconsume the gases, i.e., air or its gaseous non-noble constituents,within the enclosure 12 through an electrochemical reaction, via one ormore chemical reactions with electrochemically generated lithium, orchemical reactions between the products of these reactions andatmospheric components It is this consumption of the gas within thesealed enclosure 12 that forms the vacuum. The electrochemical cell 20lowers the pressure within the enclosure 12 through an electrochemicalreaction that takes place when a voltage is applied to the cell by thesource 24. Operation of the apparatus 20 can also be achieved bycontrolling the current supplied to the electrochemical cell 20 by thepower source 24.

FIG. 3 illustrates the operation of the electrochemical cell 20 inaccordance with a first embodiment of the invention. In this embodiment,the cathode 40 is formed of a material that does not form alloys withlithium, such as nickel or copper. Because of this construction, theelectrochemical reaction that takes place during operation of theelectrochemical cell 20 results in the electrodeposition of the Li metalfrom the lithium-ion SPE 30 onto the cathode 40, while the anode 50releases Li⁺ ions into the SPE. The electrochemical cell 20, being incontact with the environment within the enclosure 12, allows the gaseswithin the enclosure to permeate through the SPE 30 and thus react withthe electrodeposited Li metal and/or its alloys on the cathode 40. Sincemetallic Li electrodeposits are often dendritic in shape, dendrites 60formed on the cathode have large specific areas that are exposed to theenvironment within the enclosure and thus provide optimum conditions forpromoting reactions with the gases in the enclosure 12.

The reactions between metallic Li and the gases within the enclosurewould include:

6Li+N₂→2Li₃N;

4Li+O₂→2Li₂O;

2Li+H₂O→LiOH+LiH

Li₂O+H₂O→2LiOH

4Li+O₂+2H₂O→4LiOH

The amount of lithium available for electrodeposition on the cathode 40is determined primarily on the amount of Li⁺ ion contained within theanode 50 which, advantageously, can be selected to be equal to orgreater than the amount required to react with the entire volume of gaspresent within the enclosure 12. Alternatively, the amount of Li⁺ ioncontained within the anode 50 can be selected to react with a desiredamount or portion of the volume of gas present within the enclosure 12in order to achieve a desired pressure reduction in the enclosure 12.Additionally, the amount of lithium can be selected to leave some leftunconsumed after the initial vacuum formation. Advantageously, thisexcess lithium can consume gases that subsequently enter the enclosuredue to leakage.

From the above, and referring now to FIG. 4, it will be appreciated thatthe system 10 and apparatus 20, having the construction and operationdescribed with reference to FIG. 3, performs a method 100 for forming avacuum in an enclosed structure. The method 100 includes the step 102 ofproviding an enclosure, and the step 104 of providing an electrochemicalcell with a cathode exposed to the gases in the enclosure. The method100 further includes the step 106 of activating the electrochemical cellto cause electrodeposition of a reactive metal on the cathode. Thereactive metal on the cathode reacts with the gases in the enclosure toreduce the pressure in the enclosure, thus forming a vacuum therein.

Referring to FIG. 5, the step 104 of providing an electrochemical cellincludes the step 110 of providing a solid polymer electrolyte (“SPE”).The step 104 also includes the step 112 of providing a cathode on theSPE, the cathode comprising a material with which lithium does notalloy, such as nickel or copper. The step 104 also includes the step 114of providing a lithium ion anode on the SPE (e.g., a lithium alloy anodeor a lithiated transition metal oxide anode).

In another aspect, referring now to FIG. 6, the system 10 and apparatus20 having the construction and operation described with reference toFIG. 3, performs a method 120 for forming a vacuum in an enclosedstructure. The method 120 includes the step 122 of operating anelectrochemical cell to electrodeposit lithium onto an electrode(cathode). The method 120 also includes the step 124 of reacting thelithium with non-noble gases in a sealed enclosure to consume thosegases and thereby lower the pressure in the enclosure.

FIG. 7 illustrates the operation of the electrochemical cell 20 inaccordance with a second embodiment of the invention. In thisembodiment, the cathode 40 is formed of a material that forms alloyswith lithium, such as silicon or tin. Because of this construction, theelectrochemical reaction that takes place during operation of theelectrochemical cell 20 differs from that shown and described withreference to FIG. 3.

In the embodiment of FIG. 7, the lithium reaction with silicon is analloying reaction that results in the formation of a lithium alloy. Thereaction starts at the surface and destroys the crystal structure(lattice) of the host material, i.e., Si or Sn. Alternatively, dependingon the materials used to form the cathode, instead of alloying, thelithium could intercalate into an activated cathode material, formingLiC6 (lithium in graphite). In either case, the lithiumalloy/intercalated lithium reacts with and consumes the gases in theenclosure 12, which reduces the pressure in the enclosure.

Again, as with the first embodiment, the reactions between the lithiumin the lithium alloy/intercalated lithium and the gases within theenclosure would include (where the alloying element has been omitted forclarity):

6Li+N₂→2Li₃N;

4Li+O₂→2LiO;

2Li+H₂O→LiOH+LiH

Li₂O+H₂O→2LiOH

4Li+O₂+2H₂O→4LiOH

Similarly, the amount of lithium available for alloying with the cathode40 is determined primarily on the amount of Li⁺ ion contained within theanode 50 which, advantageously, can be selected to be equal to orgreater than the amount required to react with the entire volume of gaspresent within the enclosure 12. Alternatively, the amount of Li⁺ ioncontained within the anode 50 can be selected to react with a desiredamount or portion of the volume of gas present within the enclosure 12in order to achieve a desired pressure reduction in the enclosure 12.Additionally, the amount of lithium can be selected to leave some leftunconsumed after the initial vacuum formation. Advantageously, thisexcess lithium can consume gases that subsequently enter the enclosuredue to leakage.

In this embodiment, the cathode 40 could be constructed of anelectrically conductive mesh material (e.g., Cu or Ni) onto whichsilicon or tin can be deposited as films or in the form of smallparticles supported on a highly conductive material, such as carbon,using a non-volatile polymeric binder. This construction would improvethe current conducting properties of the cathode 40.

Intercalation of lithium into the cathode 40 causes the volume of thecathode 40 to increase, which can result in mechanical stresses thatlead the cathode structure to crack, fissure, or otherwise rupture. Thispossibility is shown in FIG. 7. Referring to FIG. 7, thesecracks/fissures 70 could be advantageous in that they could furtherexpose the lithium alloy contained in the cathode 40 to the gases in theenclosure 12 and furthers the reaction with those gases.

From the above, and referring now to FIG. 8, it will be appreciated thatthe system 10 and apparatus 20 of the second embodiment shown anddescribed in reference to FIG. 7 are used to perform a method 200 forforming a vacuum in an enclosed structure. The method 200 includes thestep 202 of providing an enclosure, and the step 204 of providing anelectrochemical cell with a cathode exposed to the gases in theenclosure. The method 200 further includes the step 206 of activatingthe electrochemical cell to cause a reactive metal to alloy with thecathode of the electrochemical cell. This alloy reacts with the gases inthe enclosure.

Referring to FIG. 9, it will be appreciated that the system 10 andapparatus 20 of the second embodiment are also used to perform a method210 for forming a vacuum in an enclosed structure. The method 210includes the step 212 of operating an electrochemical cell to formlithium alloys on a cathode. The method 210 also includes the step 214of reacting the lithium alloy with non-noble gases in a sealed enclosureto consume those gases and thereby lower the pressure in the enclosure.

From the above, those skilled in the art will appreciate that theapparatus 20 allows for the formation of a vacuum in the enclosurewithout requiring the use of the pumps and other equipment traditionallyassociated with vacuum formation. The electrochemical cell 22 isoperable to consume the non-noble gases in the enclosure 12 to form thevacuum. Thereafter, the electrochemical cell 22 can be used to maintainthe vacuum in the enclosure by reacting with leaked gases. Since thetotal amount of Li in the anode 50 will control the amount of gas theapparatus 20 is capable of removing, its size can be selectedaccordingly.

Depending on the materials used to construct the electrochemical cell20, the cell may require the addition of certain components tofacilitate its operation. For example, in order to raise the ionicconductivity of solutions of a Li salt in PEO, the temperature of thePEO may be raised up to several tens of degrees centigrade. Toaccomplish this, the cell may include a heater. Once the system beginsto work and the pumping action starts, the ability of the heater to heatup the thin battery will increase as there will be no source of heatdissipation except through the wires that connect the thin battery tothe outside world. The latter would be avoided by having the batteryinternal to the enclosure and well isolated thermally.

The sealed enclosure 12 is formed with the apparatus 20 disposedtherein. The apparatus 20 is inert until activated from outside theenclosure 12 to form the vacuum. To accomplish this, the apparatus 20can include actuation means 26, which is illustrated schematicallybecause it can take on various forms. For example, the actuation means26 can include electronics or circuitry that is adapted to activate theapparatus remotely and/or wirelessly. Advantageously, theelectronics/circuitry of the actuation means 26 can deactivate theapparatus 20 and subsequently reactivate the apparatus when the pressurein the enclosure 12 increases due, for example, to gassing through theenclosure. To this end, the electronics/circuitry of the actuation means26 can be adapted to monitor the pressure within the enclosure 12.

As another example, the actuation means 26 can be configured fornon-electronic manual or mechanical activation. This can beadvantageous, for instance, in implementations where cost is a concern.In this implementation, the actuation means 26 can include, for example,a rupturable member that, when destroyed, completes the circuit betweenthe source 24 and the electrochemical cell 22. Alternatively, theactuation means 26 can be a removable member that, when removedmanually, completes the circuit between the source 24 and theelectrochemical cell 22. This can, for example, be a removable strip ortape that insulates the source 24 from the electrochemical cell 22. As afurther alternative, the actuation means can be a mechanism that isactuated magnetically to complete the circuit between the source 24 andthe electrochemical cell 22. This can be achieved, for example, in amanner similar to that used to secure/release magnetic security tagscommonly found in department stores and the like.

In yet another example, the actuation means 26 can incorporate the useof radiofrequency (“RF”) transducers/tags and interrogators/receivers.For instance, the actuation means 26 can include an RF tag/switch thatallows the electrochemical cell 22 to be activated/deactivated via an RFinterrogator/receiver. The actuation means 26 can also include an RFtransducer that will return an indication that a certain (high) pressurehas been attained in the enclosure when interrogated with the same RFinterrogator/receiver. Thus, once the desired vacuum is achieved in theenclosure 12, the electrochemical cell 22 can be deactivated remotelyvia RF control. Thereafter, the pressure in the enclosure 12 can bemonitored periodically and, when it reaches the predetermined level, theelectrochemical cell 22 can be reactivated via RF control.

In a further example, the power supply 24 could be external to theenclosure 12, and fed to the electrochemical cell 22 via sealedelectrical feedthroughs in the walls of the enclosure 12, e.g., socketsor pins, that allow fully controlled operation of the apparatus externalto the enclosure.

As yet another example, the power supply 24 and/or actuation means 26could include a wireless inductive charging power supply that uses anelectromagnetic field to transfer energy from a charging unit outsidethe enclosure 12 to the electronics in the enclosure. In this instance,a charging unit with an inductive transmitting coil would generate anelectromagnetic field that excites an inductive receiving coil componentof the power supply 24 in the enclosure. These coils cooperate to forman inductive coupling for powering or charging the electrochemical cell20.

According to another aspect of the invention, the apparatus 20 caninclude a heater 28 for heating the electrochemical cell 22 within theenclosure 12. This is shown in FIG. 10. The apparatus 20 shown in FIG.10 is identical to the apparatus shown in and described with referenceto FIGS. 1-9, with the heater 28 being added to the embodiment of FIG.10. The heater 28 can have any configuration consistent with thedescription of the invention set forth herein. For example, the heater28 can be a simple resistive heating element that is an integral portionof the apparatus 20 located within the enclosure 12. Alternatively, theheater could be an electromagnetic radiation (e.g., microwave) heatsource located outside the enclosure 12.

In the example configuration illustrated in FIG. 10, the heater 28 isconnected to and powered by the power source 24. The heater 28 could,however, be powered via an alternative source, such as a magnetic fieldpower source that powers the heater via induction. As a matter ofconvenience and economy, the manner in which the heater 28 is poweredand operated can be selected to coincide with the manner in which theelectrochemical cell 22 is powered and operated. Thus, as shown in FIG.10, the apparatus 20 can be configured so that both the electrochemicalcell 22 and the heater 28 are powered by the power source 24 andactuated by the actuation means 26.

In operation, the heater 28 functions to raise the temperature of theelectrochemical cell 22 during operation. The heater 28 can beconfigured and arranged to have the ability to raise the temperature ofthe electrochemical cell 22 in the order of tens of degrees centigradeor more. Since temperature affects the rates of metal deposition and themicrostructure of electrodeposits, the ability to control thetemperature of the electrochemical cell 22 can allow for controlling therates of the resulting reactions. It therefore follows that includingthe heater 28 and implementing the ability to control its functionallows for tailoring the operation of the electrochemical cell 22 inorder to produce desired results, i.e., desired rates and degrees ofvacuum formation.

From the description set forth herein, those skilled in the art willappreciate that the system, method, and apparatus of the inventionrelates to the concept of electrochemically producing a material, eitheran element, alloy, or chemical compound, that will react withatmospheric components for the purpose of creating a vacuum within anenclosure. The electricity for producing this electrochemical reactioncan be supplied by any suitable source, such as a battery, capacitor,fuel cell or any other device capable of generating electricity. Incertain implementations, the electricity could be supplied via a powersupply connected by cord or cable to an electrical outlet.

The materials produced through the chemical reaction can be the alkalimetals described above (e.g., lithium) and can also include alkalineearth metals, such as magnesium. In this case, metallic magnesium couldbe electroplated on a metallic grid or foam electrode using a magnesiumsalt dissolved in polyethylene oxide incorporating a non volatile ionicliquid as the electrolyte (see, for example, Kumar et al. ElectrochimicaActa 56 (2011) 3864-3873), and a cathode containing, for example,nanoscale Chevrel Mo₆S₈ in powder form (see, for example, Ryu, A.; Park,M. S.; Cho, W.; et al. Bulletin of the Korean Chemical Society 34,3033-3038 (2013) or one of many other materials known to intercalatemagnesium ion (see, for example, Gershinsky, G.; Yoo, Hyun D.; Gofer,Y.; et al. Langmuir 29, 10964-10972 (2013)).

In the case of magnesium, the reactions between the magnesium alloy andthe gases within the enclosure would include (where the alloying elementhas been omitted for clarity):

3Mg+N₂→Mg₃N₂;

2Mg+O₂→2MgO;

MgO+H₂O→Mg(OH)₂

or

2Mg+O₂+2H₂O→2Mg(OH)₂

Transition metals can also be used. Examples of these are manganese,iron, cobalt, nickel, copper, and zinc. Other transition metals can beused, although their uses may be cost prohibitive. Additionally, rareearth elements (i.e., the lanthanides plus scandium and yttrium) canalso be used.

These transition metals can include nanoparticles or nanodomains ofmanganese, iron, cobalt, nickel, copper, and zinc which can be generatedby the electrochemically induced conversion of salts, such as fluorides,oxides, or sulfides of these metals in the presence of lithium ions inthe electrolyte which would produce the corresponding lithium saltsaccording to the generalized reaction:

MX_(n)+nLi⁺+ne⁻→nLiX+M;

where M represents a transition metal (e.g., Mn, Fe, Co, Ni, Cu, or Zn),X represents oxygen, sulfur, or fluorine, n represents the subscriptappropriate for the compound or the proper coefficient for balancing thereaction.

In one particular example, nanometric forms of metallic iron readilyreacts with oxygen to form iron oxides in an irreversible fashion. Inthis instance, the above equation would be:

4Fe+3O₂=2Fe₂O₃

Advantageously, this construction can be found in battery applicationsas a means for storing energy. Using such a battery as the power source24 for the electrochemical cell 22 in the sealed enclosure 20 (seeFIG. 1) would therefore advantageously remove oxygen from the enclosurewhile simultaneously powering the cell to remove other gases. In thisexample, care would have to be exercised so that the oxygen in theenclosure is not completely consumed prior to consuming the otherconsumable gases. Alternatively, the enclosure 20 could be flushed withoxygen prior to its being sealed and the battery could be activatedtherein in a simple circuit with a resistive load.

In fact, this approach could be used with any of the electrochemicalcells described herein, and could be used with inexpensive gases inaddition to or other than oxygen, such as carbon dioxide. The gasescould be introduced during construction of the enclosure, prior to itsbeing sealed. When the enclosure is filled with the gas, it can besealed with the electrochemical cell and power source installed therein.Once the cell/power source is activated, the gas will be consumedthrough the reactions described herein. Advantageously, this can avoidleaving noble gases, such as argon, in the enclosure. Since noble gaseswill not react with the metals in the electrochemical cell, they cannotbe removed electrochemically. Removing noble gases such as argon priorto sealing the enclosure solves this and, in doing so, allows theelectrochemical reaction to form a more complete vacuum.

As a further alternative, a water aspirator or a mechanical pump couldbe used to reduce the pressure in the sealed enclosure prior toactivating the electrochemical cell. This would serve to reduce thepressure in the enclosure and therefore reduce the size of theelectrochemical cell required to achieve the desired level of vacuum inthe enclosure.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications. These and othersuch improvements, changes and modifications within the skill of the artare intended to be covered by the appended claims.

1. An apparatus for consuming gases in an enclosure through an electrochemical reaction, comprising: an electrochemical cell comprising a cathode, an anode, and a solid electrolyte, wherein: the solid electrolyte is a Li-ion non-volatile electrolyte containing a dissolved metal salt, the cathode is constructed of a material with which lithium is known to form alloys, and the anode is constructed of a lithium-ion containing material; and wherein the cell is operable to expose at least one of a lithium metal and a lithium alloy on the cathode.
 2. The apparatus recited in claim 1, wherein the solid electrolyte comprises a solid polymer electrolyte (“SPE”).
 3. The apparatus recited in claim 2, wherein the SPE comprises a lithium hexafluorophosphate (LiPF₆) solution in polyethylene oxide (“PEO”). The apparatus recited in claim 1, wherein the cathode is constructed of at least one of nickel, copper, silicon, and tin.
 4. The apparatus recited in claim 1, wherein the anode is constructed of a lithium alloy.
 5. The apparatus recited in claim 1, wherein the solid electrolyte has a thin, flat, and elongated planar configuration, wherein the cathode and anode are deposited on the in an interdigitated configuration.
 6. The apparatus recited in claim 5, wherein the electrochemical cell has a construction capable of conforming to the shape of a portion of the enclosure.
 7. The apparatus recited in claim 1, further comprising a source of power, such as a battery, for powering the cell.
 8. The apparatus recited in claim 1, wherein the cathode is constructed of a material that does not form alloys with lithium, such as copper or nickel, wherein the electrochemical cell when actuated deposits lithium metal from the solid electrolyte onto the cathode while the anode releases lithium ions into the solid electrolyte, the gases within the enclosure permeating the solid electrolyte and reacting with the lithium metal on the cathode.
 9. The apparatus recited in claim 1, wherein the cathode is constructed of a material that forms alloys with lithium, such as silicon and tin, wherein the cell is operable to cause lithium to alloy with the alloying material in the cathode, causing the cathode to rupture and expose the lithium alloy to the gases in the enclosure.
 10. The apparatus recited in claim 9, wherein the solid electrolyte comprises a solid polymer electrolyte (“SPE”) comprising a Li-ion non-volatile electrolyte containing a dissolved metal salt.
 11. The apparatus recited in claim 9, wherein the anode is constructed of a lithiated transition metal oxide, such as lithium cobalt oxide (LiCoO₂).
 12. The apparatus recited in claim 9, wherein the cathode is constructed of a mesh material coated with a layer of silicon or tin.
 13. The apparatus recited in claim 1, further comprising actuation means comprising electronics or circuitry that is adapted to activate the apparatus.
 14. The apparatus recited in claim 13, wherein the actuation means is adapted to monitor pressure in the enclosure and activate/deactivate apparatus in response to pressure in the enclosure.
 15. The apparatus recited in claim 13, wherein the actuation means is adapted for non-electronic manual or mechanical activation comprising at least one of: a rupturable member that, when destroyed, actuates the electronics or circuitry; a removable member that, when removed manually, actuates the electronics or circuitry; and a mechanism that is actuated magnetically to actuate the electronics or circuitry.
 16. The apparatus recited in claim 13, wherein the actuation means comprises at least one of RF transducers, tags, interrogators, and receivers adapted to provide information regarding the apparatus and actuate the apparatus in response to an RF signal applied externally to the enclosure via a controller.
 17. The apparatus recited in claim 13, wherein the actuation means comprises sealed electrical feedthroughs in the walls of the enclosure that provide for wired connections to the apparatus from outside the enclosure.
 18. The apparatus recited in claim 13, wherein the actuation means comprises a wireless inductive charging power supply.
 19. A method for forming a vacuum in an consuming gases in an enclosed structure, comprising: providing an enclosure; providing an electrochemical cell with a cathode exposed to the gases in the enclosure; and activating the electrochemical cell to cause electrodeposition of a reactive metal on the cathode, which reacts with the gases in the enclosure.
 20. The method recited in claim 19, wherein the step of providing an electrochemical cell comprises: providing a solid electrolyte; providing a cathode on the solid electrolyte, the cathode comprising a material with which lithium does not form alloys, such as nickel or copper; and providing an anode on the solid electrolyte, the anode comprising a lithium-ion containing material, such as a lithium alloy or a lithiated transition metal oxide.
 21. A method for consuming gases in an enclosed structure, comprising: operating an electrochemical cell to electrodeposit lithium onto an electrode (cathode); and reacting the lithium with non-noble gases in a sealed enclosure to consume those gases.
 22. A method for consuming gases in an enclosed structure, comprising: providing an enclosure; providing an electrochemical cell with a cathode exposed to the gases in the enclosure; and activating the electrochemical cell to form reactive metal alloys with the cathode of the electrochemical cell that react with the gases.
 23. A method for consuming gases in an enclosed structure, comprising: operating an electrochemical cell to form lithium alloys with a cathode; and reacting the lithium alloy with non-noble gases in a sealed enclosure to consume those gases.
 24. A method for consuming gases in an enclosed structure, comprising: operating an electrochemical cell to cause lithium to alloy with a cathode; and reacting the alloyed lithium with non-noble gases in a sealed enclosure to consume those gases.
 25. The apparatus recited in claim 10, further comprising actuation means comprising electronics or circuitry that is adapted to activate the apparatus remotely from outside the enclosure. 